1. Scope of Invention
This invention relates generally to swimming pool maintenance, and more particularly to a swimming pool acid dispensing system which automatically adds acid into the water circulation system of the swimming pool by suction to modify the pH level of the water.
2. Prior Art
It is well-known that the water in a swimming pool must be chemically modified to maintain its suitability for swimming. Among other chemicals and additives, the addition of swimming pool acid to maintain the pH neutral level of the swimming pool water is required to compensate for the tendency of the swimming pool water to become alkali after use. Such swimming pool acid is normally a diluted hydrochloric acid or "muriatic" acid solution.
The addition of swimming pool acid is typically done manually wherein the attendant will monitor the acid level by visual testing and thereafter add a "guesstimated" amount of acid to modify the pH level of water. Retesting is required.
In manually introducing acid into the swimming pool water, the attendant must handle the acid container and be exposed to fumes and possible direct contact with the acid itself. Additionally, the "guesstimate" of the proper amount of acid to be added may lead to over-acidifying the swimming pool water.
In introducing acid into the swimming pool water, it is preferred to do so after the water circulation system has been activated for a period of time so as to balance the preexisting level of chemicals within the swimming pool water.
Several systems for automatically introducing acid into the swimming pool have been disclosed in prior patents. One such device is disclosed in U.S. Pat. No. 4,381,240 invented by Russell which teaches a swimming pool water conditioning system which includes a manifold system for introducing acid into the water flow system.
Armburst, in U.S. Pat. No. 3,139,402 teaches a method of introducing both acid and chlorine into the swimming pool circulation system, but no time or volume regulation of the amount of acid introduced is disclosed, nor are there any details of any valve arrangement for this invention.
In U.S. Pat. No. 3,474,817, Bates discloses a chemical additive dispenser for swimming pool systems which includes a chlorinator requiring two separate inlet and outlet connections into the water circulation system as do other prior arrangements. The chlorinator appears to be regulated by metering of fluid into the bypass arrangement, rather than being of a timed nature.
Wellman in U.S. Pat. No. 3,804,253 also teaches an automatic chlorination and pH regulating system which feeds both chlorine and acid into a mixing chamber which is, in turn, tied directly into the water circulation system in parallel fashion, again requiring two separate conduits connected to the inlet and outlet sides of the mixing chamber.
Applicant is also aware of the invention of Severin disclosed in U.S. Pat. No. 4,016,079 teaching an automatic chlorine and pH control apparatus for swimming pools which includes a means for monitoring chlorine and acid level along with a flow-through acidifier, the entire arrangement connected in parallel with the pressure and suction sides of the pump of the water circulation system.
The present invention provides a simple one line connection arrangement for a delayed time introduction of acid into a swimming pool system. The invention takes advantage of the suction pressure side of the water circulation system, thus requiring only a single line connection. A sequential arrangement of two timers delays the introduction of acid into the swimming pool water for a first period of about an hour following the activation of the swimming pool pump to allow existing chemicals in the pool water to remix and stabilize. The second timer then allows acid to flow through a unique valve from an acid supply into the swimming pool system for a second period of about thirty to sixty seconds only. This timed sequence occurs each time the pump is activated, typically on a daily twenty four hour basis.